Chinese officials have denied enforcing arbitrary detention and political re-education across a network of secret camps, instead saying that some citizens guilty of minor offences were sent to vocational centres to provide future employment opportunities.

China's far-western Xinjiang region has authorized the setting up of vocational training camps for Muslim Uighurs to crack down on people influenced by extremism, an official said Thursday.

On Tuesday, a newly revised edition was released with passages referring for the first time to "vocational training centers", casting them as part of the government's efforts to counter extremism.

But James Leibold, a scholar of Chinese ethnic policies at Melbourne's La Trobe University, said: 'It's a retrospective justification for the mass detainment of Uighurs, Kazakhs, and other Muslim minorities in Xinjiang.

In 2017, China banned activity deemed "extremist" was banned, including wearing a headscarf, having "abnormal" beards, refusing to follow state media, or preventing children from receiving state education.

Government officials should also not have dietary restrictions, the statement said, adding work canteens would be changed so officials can try "cuisines of various nationalities".

Uighurs and other Muslim minorities are subject to strict regulations banning beards and burqas, and many have been detained in re-education camps for offences as minor as making contact with family members outside the country or sharing Islamic holiday greetings on social media, a United Nations report said in August. China has come under increasing pressure from the USA and the European Union after a United Nations panel confronted Chinese diplomats in August over reports of arbitrary mass detentions and harsh security measures aimed at Muslims.

"Regardless of these revisions I still believe the practice of coercively detaining Uighurs and other Muslim minorities in Xinjiang in "education through transformation centres" not only violates Chinese law but also global legal norms against the extrajudicial deprivation of liberty", Leibold said.